Snap-on Liner Retention Device

ABSTRACT

A shaped charge retainer ring for use in containing the liner of a shaped charge and the explosive material.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/142,099, filed Apr. 2, 2015.

BACKGROUND OF THE INVENTION

Generally, when completing a subterranean well for the production offluids, minerals, or gases from underground reservoirs, several types oftubulars are placed downhole as part of the drilling, exploration, andcompletions process. These tubulars can include casing, tubing, pipes,liners, and devices conveyed downhole by tubulars of various types. Eachwell is unique, so combinations of different tubulars may be loweredinto a well for a multitude of purposes.

A subsurface or subterranean well transits one or more formations. Theformation is a body of rock or strata that contains one or morecompositions. The formation is treated as a continuous body. Within theformation hydrocarbon deposits may exist. Typically a wellbore will bedrilled from a surface location, placing a hole into a formation ofinterest. Completion equipment will be put into place, including casing,tubing, and other downhole equipment as needed. Perforating the casingand the formation with a perforating gun is a well-known method in theart for accessing hydrocarbon deposits within a formation from awellbore.

Explosively perforating the formation using a shaped charge is a widelyknown method for completing an oil well. A shaped charge is a term ofart for a device that when detonated generates a focused explosiveoutput. This is achieved in part by the geometry of the explosive inconjunction with a liner in the explosive material. Generally, a shapedcharge includes a metal case that contains an explosive material with aconcave shape, which has a thin metal liner on the inner surface. Manymaterials are used for the liner; some of the more common metals includebrass, copper, tungsten, and lead. When the explosive detonates theliner metal is compressed into a super-heated, super pressurized jetthat can penetrate metal, concrete, and rock.

A perforating gun has a gun body. The gun body typically is composed ofmetal and is cylindrical in shape. Within a typical gun tube is a chargeholder, which is a tube that is designed to hold the actual shapedcharges. The charge holder will contain cutouts called charge holeswhere the shaped charges will be placed.

A shaped charge is a term of art for a device that when detonatedgenerates a focused explosive output. This is achieved in part by thegeometry of the explosive in conjunction with a liner in the explosivematerial. Many materials are used for the liner; some of the more commonmetals include brass, copper, tungsten, and lead. When the explosivedetonates the liner metal is compressed into a super-heated, superpressurized jet that can penetrate metal, concrete, and rock.

Within a typical gun tube is a charge holder, which is a tube that isdesigned to hold the actual shape charges. The charge holder willcontain cutouts called charge holes where the shape charges will beplaced. A typical shaped charge is carried in a cylindrical perforatinggun.

Typically, the liner is held within the shaped charge case using anadhesive material. Adhesives present issues during the manufacturingprocess that incur additional costs and have environmental issues. Aneed exists for a means of cheaply retaining a liner and explosivematerial within the shaped charge case without using adhesives.Additionally, it is desirable to place an insulating and non-sparkingmaterial on the shaped charge cases for a variety of reasons includingsafety.

SUMMARY OF EXAMPLES OF THE INVENTION

An example embodiment is a shaped charge apparatus having a shapedcharge case with an axis, an inner surface, an outer surface, and a topsurface, and at least one circumferential groove on the outer surface.An L-shaped inner retainer ring with an inner radial surface, an outerradial surface, a lower axial surface, and an upper axial surface may beattached to the shaped charge case. The lower axial surface of the innerretainer ring may be adjacent to the top surface of the shaped chargeand the outer radial surface maybe adjacent to the inner surface of theshaped charge. Another L-shaped outer retainer ring having an upperaxial surface, a lower axial surface, an inner radial surface, and anouter radial surface, may be attached to the top of the L-shaped innerring. The inner radial surface of the outer retainer ring may include atleast one circumferential groove interfaced with the shaped charge outersurface circumferential groove. The shaped charge may include a linerwith an inner surface and an outer surface. The liner may be restrainedaxially by the inner retainer ring and the outer retainer ring. Anexplosive material may be located between the outer surface of the linerand the inner surface of the shaped charge case.

A variation of the example embodiment may include the onecircumferential groove on the outside surface of the shaped charge casebeing a plurality of circumferential grooves. At least onecircumferential groove on the inner radial surface of the outer retainerring may be a plurality of circumferential grooves. The inner retainerring may be composed of plastic. The outer retainer ring may be composedof plastic. The outer retainer ring and the inner retainer ring may beintegrally formed into a single retainer ring. The inner retainer ringmay be rated to function up to 400 degrees Fahrenheit. The outerretainer ring may be rated to function up to 400 degrees Fahrenheit. Theinner retainer ring may have a low electrical conductivity. The outerretainer ring may have a low electrical conductivity. The inner retainerring may be manufactured using an additive manufacturing process. Theouter retainer ring may be manufactured using an additive manufacturingprocess.

Another example embodiment may include a method for making a shapedcharge by forming explosive material inside of a shaped charge case,forming a liner over the explosive material, and installing a firstretainer ring onto the shaped charge case. The retainer ring may preventaxial movement of the liner and the explosive material within saidshaped charge case.

A variation of the example embodiment may further include installing asecond retainer ring to the shaped charged case. The example may includeinstalling the shaped charge in a charge tube. The second retainer ringmay prevent axial movement of the first retainer ring. The forming of aliner may result in a substantially frusto-conical shape. The forming ofexplosive material may result in a substantially frusto-conical shape.The example embodiment may include electrically isolating the shapedcharge. It may include manufacturing the first retainer ring. It mayinclude manufacturing the second retainer ring. The manufacturing of thefirst retainer ring may include an additive manufacturing process. Themanufacturing of the second retainer ring may include an additivemanufacturing process.

Another example embodiment may include a shaped charge with a casehaving an apex end, an open end having a rim, and a cavity extendinginto case from the open end. It may have a liner fitted into the openend of the case. It may have an electrically insulating ring adapted tofit over the rim of the open end of the case.

A variation of the example embodiment may include the rim of the openend of the case being substantially circular. It may have asubstantially cylindrical inner surface and a substantially cylindricalouter surface and the insulating ring being substantially circular and asubstantially cylindrical inner surface and a substantially cylindricalouter surface. The inner surface of the insulating ring may have asmaller diameter than the inner surface of the open end of the case. Theouter surface of the rim of the case may have a retention feature. Theretention feature may include a raised circumferential ridge, aplurality of raised circumferential ridges, a circumferential groove, ora plurality of circumferential grooves. The inner surface of the rim ofthe case may have a retention feature that may include a raisedcircumferential ridge, a plurality of raised circumferential ridges, acircumferential groove or a plurality of circumferential grooves.

Further variations of the embodiment may include the inner surface ofthe insulating ring with a retention feature. The retention feature mayinclude a raised circumferential ridge, a plurality of raisedcircumferential ridges, a circumferential groove, or a plurality ofcircumferential grooves.

Further variations of the embodiment may include the outer surface ofthe insulating ring having a retention feature of a raisedcircumferential ridge, a plurality of raised circumferential ridges, acircumferential groove, or a plurality of circumferential grooves.

Further variations of the embodiment disclosed may include the rim ofthe open end of the case being substantially circular and having asubstantially cylindrical inner surface. It may also have asubstantially cylindrical outer surface. It may also have the insulatingring having a substantially circular end face, a substantiallycylindrical inner wall extending axially from the end face, and asubstantially cylindrical outer wall extending axially from the endface. The outer wall of the insulating ring may be adapted to fitoutside the outer surface of the rim of the case. The outer wall of theinsulating ring may include a retention feature adapted to engage aretention feature on the outer surface of the rim of the case. The innerwall of the insulating ring may be adapted to fit inside the innersurface of the rim of the case. The inner wall of the insulating ringmay have a retention feature adapted to engage a retention feature onthe inner surface of the rim of the case.

BRIEF DESCRIPTION OF THE DRAWINGS

For a thorough understating of the present invention, reference is madeto the following detailed description of the preferred embodiments,taken in conjunction with the accompanying drawings in which referencenumbers designate like or similar elements throughout the severalfigures. Briefly:

FIG. 1 is cross section of an example perforating gun.

FIG. 2 is a cross section view of a shaped charge with an inner retainerring and an outer retainer ring.

FIG. 3 is a cross section view of a shaped charge with a single retainerring.

DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION

In the following description, certain terms have been used for brevity,clarity, and examples. No unnecessary limitations are to be impliedtherefrom and such terms are used for descriptive purposes only and areintended to be broadly construed. The different apparatus, systems andmethod steps described herein may be used alone or in combination withother apparatus, systems and method steps. It is to be expected thatvarious equivalents, alternatives, and modifications are possible withinthe scope of the appended claims.

Referring to FIG. 1, a typical perforating gun 10 includes a gun body 11that houses the shaped charges 12. The gun body 11 contains end fittings16 and 20 which secures the charge tube 18 into place. The charge tube18 has charge holes 23 that are openings where shaped charges 12 may beplaced. The gun body 11 has threaded ends 14 that allow it to beconnected to a series of perforating guns 10 or to other downholeequipment depending on the job requirement. Other design variations mayuse ends that are bolted together. In FIG. 1, a 60 degree phase gun isshown where each shaped charge 12 is rotated about the center axis by 60degrees from one shaped charge to the next. Each shaped charge 12 has acorresponding scallop 21 milled into the gun body 11. Other embodimentsof this design are possible including zero degree phase guns, where allthe shaped charges are aligned. Other end fittings or connections couldbe used in lieu of threaded fittings, such as bolted fittings.

Referring to FIG. 2, an example embodiment is a shaped charge 116 with ashaped charge case 111 having an axis 117, an inner surface 108, anouter surface 118, and a top surface 107. Shaped charge case 111 hascircumferential groove 103 on the outer surface 118. An L-shaped innerretainer ring 115 with an inner radial surface 109, an outer radialsurface 119, a lower axial surface 120, and an upper axial surface 106is attached to the top surface 107 of the shaped charge case 111. Thelower axial surface 120 is adjacent to the top surface 107 of the shapedcharge case 111. The outer radial surface 119 is adjacent to the innersurface 108 of the shaped charge case 111. A L-shaped outer retainerring 102 having an upper axial surface 122, a lower axial surface 121,an inner radial surface 104, and an outer radial surface 105 engageswith the shaped charge case 111. Its inner radial surface 104 includesat least one circumferential groove 123 that is interfaced with theshaped charge outer surface circumferential groove 103. The shapedcharge 116 includes a liner 113 with an inner surface 124 and an outersurface 125. The liner 113 is restrained axially by the inner retainerring 115 and the outer retainer ring 102. An explosive material 112 islocated between the outer surface 125 of the liner 113 and the innersurface 108 of the shaped charge case 111. The shaped charge case 111has an apex end 126.

Another example embodiment may include the shaped charge case 111 havingan axis 117, an inner surface 108, an outer surface 118, and a topsurface 107 and at least one circumferential retaining feature 103 forretaining a ring on the outer surface. The retaining feature 103 may bea circumferential groove, a plurality of circumferential grooves, athread, a buttress thread, a plurality of ridges, a plurality ofdetents, a lip, or some other retaining means that is well known in theart.

A variation of the example embodiment may include a plurality ofcircumferential grooves 103 on the outside surface 118 of the shapedcharge case 111. The inner retainer ring 115 may be composed of plastic.The outer retainer ring 102 may be composed of plastic. The innerretainer ring 115 may be rated to function up to 400 degrees Fahrenheit.The outer retainer ring 102 may be rated to function up to 400 degreesFahrenheit. The inner retainer ring 115 probably has a low electricalconductivity. The outer retainer ring 102 probably has a low electricalconductivity. The inner retainer ring 115 may be manufactured using anadditive manufacturing process. The outer retainer ring 102 may bemanufactured using an additive manufacturing process.

Another example embodiment includes a method for making a shaped chargeby forming explosive material 112 inside of a shaped charge case 111,forming a liner 113 over the explosive material 112, and installing afirst retainer ring 115 onto the shaped charge case 111. The retainerring 115 prevents axial movement of the liner 113 and the explosivematerial 112 within said shaped charge case 111.

A variation of the example embodiment includes installing a secondretainer ring 102 to the shaped charged case 111. It could also includeinstalling the shaped charge 116 in a charge tube 18. The secondretainer ring 102 may prevent axial movement of the first retainer ring115. The forming of a liner 113 may result in a substantiallyfrusto-conical shape. The forming explosive material 112 may result in asubstantially frusto-conical shape. The example embodiment may furtherinclude electrically isolating the shaped charge 116. It may includemanufacturing the first retainer ring 115. It may further includemanufacturing the second retainer ring 102. The manufacturing of thefirst retainer ring 115 may include an additive manufacturing process.The manufacturing of the second retainer ring 102 may include anadditive manufacturing process.

The outer retainer ring 102 and the inner retainer ring 115 may beintegrally formed into a single retainer ring 215 as shown in FIG. 3.Another example embodiment may include a shaped charge 216 with a case211 having an apex end 226, an open end 208 having a rim 230, and acavity extending into case from the open end 208. A liner 213 is fittedinto the open end of the case. An electrically insulating ring 215 isfitted over the rim 230 of the open end 208 of the case 211. Explosivematerial 212 is located between the liner 213 and the charge case 211

A variation of the example embodiment may include the rim 230 of theopen end 208 of the case 211 being substantially circular and having asubstantially cylindrical inner surface 214. It have include asubstantially cylindrical outer surface 218. The insulating ring 215 maybe substantially circular. It may include a substantially cylindricalinner surface 231 and a substantially cylindrical outer surface 232. Theinner surface 231 of the insulating ring 215 may have a smaller diameterthan the inner surface 214 of the open end 208 of the case 211. Theouter surface 218 of the rim 230 of the case 211 may include a retentionfeature 203 such as a raised circumferential ridge, a plurality ofraised circumferential ridges, a circumferential groove, or a pluralityof circumferential grooves.

In other examples the inner surface 214 of the rim of the case mayinclude a retention feature 203 such as a raised circumferential ridge,a plurality of raised circumferential ridges, a circumferential groove,or a plurality of circumferential grooves. Further variations of theembodiment may include the inner surface 231 of the insulating ring 215having a retention feature. The retention feature may include aretention feature 203 such as a raised circumferential ridge, aplurality of raised circumferential ridges, a circumferential groove, ora plurality of circumferential grooves.

Further variations of the embodiment may include the outer surface 232of the insulating ring 215 has a retention feature 233. The retentionfeature 233 may include a retention feature 203 such as a raisedcircumferential ridge, a plurality of raised circumferential ridges, acircumferential groove, or a plurality of circumferential grooves.

Further variations of the embodiment disclosed may include the rim 230of the open end 208 of the case 211 being substantially circular. It mayhave a substantially cylindrical inner surface 214 and a substantiallycylindrical outer surface 218. The insulating ring 215 may have asubstantially circular end face 202, a substantially cylindrical innerwall 235 extending axially from the end face 202, and a substantiallycylindrical outer wall 234 extending axially from the end face 202. Theouter wall 234 of the insulating ring 215 may be adapted to fit outsidethe outer surface of the rim 230 of the case 211. The outer wall 234 ofthe insulating ring 215 may include a retention feature 233 adapted toengage a retention feature 203 on the outer surface 218 of the rim 230of the case 211. The inner wall 235 of the insulating ring 215 may beadapted to fit inside the inner surface 214 of the rim 230 of the case211. Alternatively, the inner wall 235 of the insulating ring 215 mayinclude a retention feature adapted to engage a retention feature on theinner surface of the rim 230 of the case 211.

Although the invention has been described in terms of particularembodiments which are set forth in detail, it should be understood thatthis is by illustration only and that the invention is not necessarilylimited thereto. Alternative embodiments and operating techniques willbecome apparent to those of ordinary skill in the art in view of thepresent disclosure. Accordingly, modifications of the invention arecontemplated which may be made without departing from the spirit of theclaimed invention.

What is claimed is:
 1. A shaped charge apparatus comprising: a shapedcharge case with an axis, an inner surface, an outer surface, and a topsurface; and at least one circumferential retaining means for retaininga ring on the outer surface.
 2. The apparatus of claim 1, wherein the atleast one retaining means on the outside surface of the shaped chargecase is a circumferential groove.
 3. The apparatus of claim 2, whereinthe at least one retaining means is a plurality of circumferentialgrooves.
 4. The apparatus of claim 1, wherein the retaining means is athread.
 5. The apparatus of claim 4, wherein the thread is a buttressthread.
 6. The apparatus of claim 1, wherein the retaining means is aplurality of ridges.
 7. The apparatus of claim 1, wherein retainingmeans is a plurality of detents.
 8. The apparatus of claim 1, whereinretaining means is a lip.
 9. A shaped charge retaining systemcomprising: a shaped charge case with an axis, an inner surface, anouter surface, and a top surface; at least one circumferential groove onthe outer surface; a L-shaped inner retainer ring with an inner radialsurface, an outer radial surface, a lower axial surface, and an upperaxial surface, wherein the lower axial surface is adjacent to the topsurface of the shaped charge and the outer radial surface is adjacent tothe inner surface of the shaped charge; a L-shaped outer retainer ringhaving an upper axial surface, a lower axial surface, an inner radialsurface, and an outer radial surface, wherein the inner radial surfaceincludes at least one circumferential groove that interfaced with theshaped charge outer surface circumferential groove; a liner with aninner surface and an outer surface, wherein the liner is restrainedaxially by the inner retainer ring and the outer retainer ring; and anexplosive material located between the outer surface of the liner andthe inner surface of the shaped charge case.
 10. The apparatus of claim9, wherein the at least one circumferential groove on the outsidesurface of the shaped charge case is a plurality of circumferentialgrooves.
 11. The apparatus of claim 10, wherein the at least onecircumferential groove on the inner radial surface of the outer retainerring is a plurality of circumferential grooves.
 12. The apparatus ofclaim 9, wherein the inner retainer ring is composed of plastic.
 13. Theapparatus of claim 9, wherein the outer retainer ring is composed ofplastic.
 14. The apparatus of claim 9, wherein the outer retainer ringand the inner retainer ring are integrally formed into a single retainerring.
 15. The apparatus of claim 12, wherein the inner retainer ring israted to function up to 400 degrees Fahrenheit.
 16. The apparatus ofclaim 13, wherein the outer retainer ring is rated to function up to 400degrees Fahrenheit.
 17. The apparatus of claim 9, wherein the innerretainer ring has a low electrical conductivity.
 18. The apparatus ofclaim 9, wherein the outer retainer ring has a low electricalconductivity.
 19. The apparatus of claim 9, wherein the inner retainerring is manufactured using an additive manufacturing process.
 20. Theapparatus of claim 9, wherein the outer retainer ring is manufacturedusing an additive manufacturing process.
 21. A method for making ashaped charge comprising: forming explosive material inside of a shapedcharge case; forming a liner over the explosive material; and installinga first retainer ring onto the shaped charge case, wherein the retainerring prevents axial movement of the liner and the explosive materialwithin said shaped charge case.
 22. The method of claim 21, furthercomprising installing a second retainer ring to the shaped charged case.23. The method of claim 21, further comprising installing the shapedcharge in a charge tube.
 24. The method of claim 22, wherein the secondretainer ring prevents axial movement of the first retainer ring. 25.The method of claim 21, wherein the forming a liner results in asubstantially frusto-conical shape.
 26. The method of claim 21, whereinthe forming explosive material results in a substantially frusto-conicalshape.
 27. The method of claim 21 further comprising electricallyisolating the shaped charge.
 28. The method of claim 21 furthercomprising manufacturing the first retainer ring.
 29. The method ofclaim 21 further comprising manufacturing the second retainer ring. 30.The method of claim 28 wherein the manufacturing of the first retainerring includes additive manufacturing.
 31. The method of claim 29 whereinthe manufacturing of the second retainer ring includes additivemanufacturing.
 32. A shaped charge comprising: A case having an apexend, an open end having a rim, and a cavity extending into case from theopen end; a liner fitted into the open end of the case; an electricallyinsulating ring adapted to fit over the rim of the open end of the case.33. The shaped charge of claim 32 wherein: the rim of the open end ofthe case is substantially circular and comprises a substantiallycylindrical inner surface and a substantially cylindrical outer surface;and the insulating ring is substantially circular and comprises asubstantially cylindrical inner surface and a substantially cylindricalouter surface.
 34. The shaped charge of claim 33 wherein: the innersurface of the insulating ring has a smaller diameter than the innersurface of the open end of the case.
 35. The shaped charge of claim 33wherein the outer surface of the rim of the case comprises a retentionfeature.
 36. The shaped charge of claim 35 wherein the retention featurecomprises a raised circumferential ridge.
 37. The shaped charge of claim35 wherein the retention feature comprises a plurality of raisedcircumferential ridges.
 38. The shaped charge of claim 35 wherein theretention feature comprises a circumferential groove.
 39. The shapedcharge of claim 35 wherein the retention feature comprises a pluralityof circumferential grooves.
 40. The shaped charge of claim 33 whereinthe inner surface of the rim of the case comprises a retention feature.41. The shaped charge of claim 40 wherein the retention featurecomprises a raised circumferential ridge.
 42. The shaped charge of claim40 wherein the retention feature comprises a plurality of raisedcircumferential ridges.
 43. The shaped charge of claim 40 wherein theretention feature comprises a circumferential groove.
 44. The shapedcharge of claim 40 wherein the retention feature comprises a pluralityof circumferential grooves.
 45. The shaped charge of claim 33 whereinthe wherein the inner surface of the insulating ring comprises aretention feature.
 46. The shaped charge of claim 45 wherein theretention feature comprises a raised circumferential ridge.
 47. Theshaped charge of claim 45 wherein the retention feature comprises aplurality of raised circumferential ridges.
 48. The shaped charge ofclaim 45 wherein the retention feature comprises a circumferentialgroove.
 49. The shaped charge of claim 45 wherein the retention featurecomprises a plurality of circumferential grooves.
 50. The shaped chargeof claim 33 wherein the wherein the outer surface of the insulating ringcomprises a retention feature.
 51. The shaped charge of claim 50 whereinthe retention feature comprises a raised circumferential ridge.
 52. Theshaped charge of claim 50 wherein the retention feature comprises aplurality of raised circumferential ridges.
 53. The shaped charge ofclaim 50 wherein the retention feature comprises a circumferentialgroove.
 54. The shaped charge of claim 50 wherein the retention featurecomprises a plurality of circumferential grooves.
 55. The shaped chargeof claim 32 wherein: the rim of the open end of the case issubstantially circular and comprises a substantially cylindrical innersurface and a substantially cylindrical outer surface; and theinsulating ring comprises a substantially circular end face, asubstantially cylindrical inner wall extending axially from the endface, and a substantially cylindrical outer wall extending axially fromthe end face.
 56. The shaped charge of claim 55 wherein the outer wallof the insulating ring is adapted to fit outside the outer surface ofthe rim of the case.
 57. The shaped charge of claim 55 wherein the outerwall of the insulating ring comprises a retention feature adapted toengage a retention feature on the outer surface of the rim of the case.58. The shaped charge of claim 55 wherein the inner wall of theinsulating ring is adapted to fit inside the inner surface of the rim ofthe case.
 59. The shaped charge of claim 55 wherein the inner wall ofthe insulating ring comprises a retention feature adapted to engage aretention feature on the inner surface of the rim of the case.